Static pressure regulator



J. M. LARSON 2,210,868

STATIC PRESSURE REGULATOR Filed Oct. 2, 1937 2 Sheets-Sheet l 2 4O 2 W 34 52 z y 1 INVENTOR llghn M. L a r s on ATTORNEY Allg- 6, 1940- J. M. LARSON 2.210,868

STATIC PRESSURE REGULATOR Filed Oct. 2, 193'? 2 Sheets-Sheet 2 :07 I no r J) k T 26 26 I08 I09 fi fi 1 00 lOl INVENTOR :E'iQ-S Jghn M-Larson KT TmY Patented Aug. 6, 1940 I 7 2,210,868 s-rs'rro PRESSURE ascum'roa John M. Larson, Chicago, Ill., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application October 2,

7 Claims.

The present invention is concerned with pressure regulators and pertains more particularly to regulators for maintaining a constant differential between two regions wherein different 5 pressures exist, such as between atmospheric pressure and the pressure in a conduit or the like, or for maintaining a constant pressure .in one region. a 1

In fluid circulating or distributing systems it is frequently necessary to maintain a constant pressure in certain portions of the circuit and in air circulating or ventilating systems or the like it is often desirable to maintain a constant differential between atmospheric pressure and the pressure at some point in the circulating system. To obtain this result, the fluid forcing means or the fluid flow must be governed in accordance with the pressure or the difierence in pressures depending on whether it is desired to maintain a single pressure at a constant value or to maintain a constant differential between two pressures.

The present invention will be described as applied to an air distributing system wherein it is desired to maintain a constant differential between atmospheric pressure and the pressure in the conduit orduct conveying air to the point of distribution. In such a system a, single fan may be employed to force ventilating or conditioned air to a plurality of rooms or spaces, the discharge duct from the fan branching off to distribute air to the various rooms or spaces. When the load on such a fan is varied by closing ofi branches to certain rooms or reducingthe flow in certain 35 branches, the pressure in the fan discharge duct will rise and will result in air being. circulated too rapidly to the other rooms thereby causing drafts and unstable operation of controlling instruments and the like. Frequently the increased pressure when a number of branch ducts are closed will tend to cause the main air supply duct to bulge and possibly rupture.

The above are examples of faults and disadvantages to be overcome by application of thepresent invention to an air distributing system. However, it is understood that the invention has equal applicability and utility in various other types of apparatus and in other fluid circuits and systems.

Among the objects of the invention is to provide a device for maintaining a constant differential between two pressure regions, which device is sensitive to changes in the difierential and responds accurately and quickly to such changes.

1937, Serial No. 167,073

A further object is to provide a device for maintaining a constant pressure differential, having adjustments whereby any desired diiferential may be maintained regardless of fluctuations in either of the pressures to which the device is responsive.

Another object is to provide a device for controlling a valve, damper, or the like having novel means for adjusting the so-called throttling range or sensitivity of the instrument, that is, the increment change in valve position with respect to increment change in pressure conditions.

Another object is to provide a pressure regulating device by which a pressure can be maintained accurately at any constant value.

Another object is to provide novel structure in a differential pressure regulator for adjusting the setting from one pressure or pressure differential to another and accurately and quickly bringing the system back into equilibrium.

Another object of the invention is to provide a novel structural arrangement in a bell chamber to prevent the liquid in the bell chamber from overflowing into a pipe leading to the upper portion of the bell chamber.

Various other objects and advantages of the invention will become apparent to those skilled in the art from a reading of the following detailed description and the accompanying draw- Referring to the drawings:

Figure 1 is a side elevation partly in cross section of the automatic pressure regulator as seen along line l-l of Figure 2,

Figure 2 is a cross sectional view taken along line 2--2 ofFigure 1,

Figure 3 is a plan view of a detail portion of the structure taken along line 3-3 of Figure 2,

Figure 4 is a side elevation of the detail structure of Figure 3, taken along line 4-4 of Figure 1,

Figure 5 is an enlarged view of that portion of the structure shown in detail in Figures 3 and 4: as seen in Figure 1, and

Figure 6 isa diagrammatic showing of a portion of an air distributing system having the present invention applied thereto for regulating the pressure differential between the atmosphere and that in the conduit conveying air to the point of distribution.

Referring to the drawings and more particularly to Figures 1 to 5, reference numeral I indicates a metal tank of rectilinear formation having one relatively longer and one relatively shorter dimension with the depth equal approximately to the shorter dimension. Fastened to the tank by screws or the like are longitudinal bar members 3 which are perforated at their ends and provide for mounting the tank on a vertical wall or bulkhead. Numeral 2 indicates a fiat top or 5 cover having a down-turned peripheral flange for engagement over'the top of the tank.

Within the tank and extending transversely between the side walls midway between the ends is a horizontal cross beam or me her 4. The 7 l cross member 4 has integral transv rsely extendwhich has a screw threaded portion for engaging with the vertical member Adjacent the end opposite portion 1 of cross 88 member 4 which is of generally bar-like configuration is an enlarged portion iii the sides of which have a rounded conformation and which has a depth materially less than the remaining part of cross member 4. This portion ill of the 80 cross member 4 is tapped to receive a screw i i, the upper end of which is formed as a conical point. A lock nut Ila engages the screw ii and retains it in fixed relation to the portion ill of cross member 4. e

Mounted on the knife edge 3 and the. conic point of the screw l I in balancing relation thereto is a cross member 12. Cross member i2 takes the form of a generally rectilinear bar having a depression or recess adjacent one end adapted to v 40 engage the conical point of screw it and having a portion at the opposite end notched for engagement with the knife edge 3. Cross member I! also has a depressed portion as at 18, a por-' tion of which extends horizontally from member 45 I: as shown in Figure 3 for a purpose which will be hereinafter described. Y

Integrally formed with the cross member i2 is a rectilinear bar-like member I5 which extends transversely of the member I! and longitudinally 50 within the tank I. Approximately midway between the center of the bar member l5 and each of its ends are integrally formed cylindrical portions l6. Each of the portions i6 is rigidly secured to the closed end of a bell chamber il by 5 welding 'orsoldering as shown at i8 and also .by a screw which extends through the closed end of each bell chamber and screws into the cylindrical poi tion It of the bar member I 8. The welding or soldering 'at it renders the juncture 60 of portions IS with the bell chambers airtight. Each of the bell chambers l7 comprises a gen-.

' erally cylindrical inverted vessel preferably'made of the same material as the tank I and having a metal ring i9 secured within the open end of the vessel adjacent the rim. The ring I! is secured in position by screws 20 engaging with the side walls of the bellchamber I1 and screwed into holes tapped into th'ring. Q .In sliding engagement with member ii are 70 metal counter-weights 14," having slots for slid- V ably receiving the bar member and set screws for inimovably setting the weights in any desired position with respect to the bar. Upstanding from the bottomof the tank i are 75 two wells 2| each co'mprisinggenerally a metallic carcass cylinder welded or soldered to the bottom of the tank as shown at 22. Each of these wells is posi- In the bottom of the tank i within the wells 2i are plugs or adaptor members 25 for tightly receiving conduits or pipes 26 which form standpipes within wells 2| which are in communication through the openings 24 with the interior of v the bell chambers i'l. Also at the bottom of the tank i within the wells 2| are plug members 2'! having screw threaded openings engaged by,

screws 28 which provide for draining the wells.

Tank l is filled with a liquid'sucli as a light rade of mineral oil or the like to the level as indicated at 23.

Referring again to the vertical portion I of the cross member 4 it will be seen that horizontally extending portion 8 (see Figured) provides a support for an assembly generally indicated by the numeral 30. -The assembly indicated by the numeral 30 is best shown in Figures 3 and 4 and includes a metal member 3| having :3. lug portion '32 with an arcuate slot 33 for adjustable engage- The fitting 31 is welded or soldered to the end 'of a tube 38 which will be referred to later in the description. The member 3] is drilled to receive screws 39a and 3%. Screw 391; extends through a drilled hole in member 3i which is not threaded and thereafter engages in threaded relation with the horizontal lug-like portion 8 previously described. Member 3i and thus the asresilient spring metal indicated at 4i. The shoe 40 is secured by screws to member 3i as shown (see Figure 3). The resilient spring element 4i is inserted in a rabbetedslot, or the like, in mamher 40 and provides a support for leverarm eleme'nt 42 which forms a part of a valve device in that the lever arm pivots about the seat of spring element 4i in metal shoe member 40. The

' members 4| and 42 are so mounted with respect to the metal block or shoe member 48 and the member 3| that'their plane surfaces lie substantially'in a vertical plane-as shown in Figure 3. It will-also be seen that the mounting position of the arm or lever.42.brings it adjacent to anipple or the like 43 forming a part of the fitting 81 and extending beyond the metal member 3|.

Referring now to the depressed and horizontally extending portion i3 of the crossbar II,

it will be seen that this portion-is tapped asshown 'to receive a vertical screw member 44.

Carried on the screw member 44 are two thumb nuts 45 between which is a small dog or arm 48 extent forcontacting with the extending portion of the dog 46.

Near the upper part of one side wall of tank I' is a plug member or fitting 48 which extends through an opening in the side wall of the tank and is threaded to receive a nut 49 inside the tank. The portion of the plug which is outside the tank is formed to receive a wrench or the like and is also adapted to receive a fitting or couplingfor connection to a pipe or conduit. Tightening of the nut 49 secures fitting 48 and the nut'tightly against the side walls of the tank. Fitting 48 is also internally threaded to receive coupling member 50 into which is screwed a fitting 5I at the end of the looped tube 38. The looped tube 33 is made .of resilient or flexible metal and is provided with loop 52 so that the fitting 31 at the end can be adjusted back and forth without disturbing .the connections in the side wall of the tank, the loop providing the necessary elasticity.

Figure 6 indicates more or less diagrammatically a fan having a damper in the discharge conduit thereof, and the regulator device of this invention applied thereto for the purpose of maintaining a constant differential between the static pressure in the discharge conduit and the atmosphere. Reference numeral I indicates a fan driven by a motor IOI and having a suction conduit I02 and a discharge conduit I03. Within the discharge conduit I03 is a damper I04 comprising a lever connected to a plurality of louvre members. The damper I04 is operated by a bellows motor I05 inside of the discharge conduit. Bellows motor I05 is connected by a conduit I08 through a restriction IN to a suitable source of constant air pressure from conduit I00.

The pressure regulator of this invention is suitably supported on a wall or bulkhead of the room or enclosure in which the fan I00 is located. The space within the interior of one of the previously described bell chambers conimunicates through a conduit 26 with the exterior of the building, which conduit terminates bell chamber of the regulating device communicates through a conduit 26 with a static pressure measuring element II3 located within the discharge conduit of the fan. The element II3 comprises a Jacket or casing arranged with its longitudinal axis parallel to the air stream and having orifices in its side walls arranged at right angles to the direction of flow of the air stream. Thus the element I I3 serves to communicate only static pressure through conduit 28 to the interior of the bell chamber and does not sense any pressure in the discharge conduit due to the velocity of the air moving therethrough.

mitted to bleed. Pressure in conduit I06 and indicated by the pressure gage H2 is determined by the rate at which air is permitted to be bled from the port of the nipple. 43. Thus the rate of bleeding determines the pressure in bellows motor I05 and consequently the position of the damper I04.

From the preceding structural description it is thought that it will be apparent to those skilled in the art as to the general. manner in which the invention of this application operates. However, for purposes of making more clearly apparent the utility and novelty of the device, its operation will be described in detail in connection with the fan diagrammatically shown in Figure 6.

It will be understood that the fan I00 may serve to force air through discharge conduit I03 to a number of separate rooms or enclosures. In order to insure that each of the various enclosures receives its proper volume of air at times when other rooms or spaces may be cut oil! and put out of use, it is necessary that the pressure in the discharge conduit remain constant.

I As the pressure and density of the atmosphere exterior to the building may vary it is necessary that the pressure in conduit I03 be maintained constant with respect to atmospheric pressure. If the pressure in conduit I03 were held constant irrespective of changes in atmospheric pressure, the volumes of air forced to individual rooms or spaces would be erratic due to the variations in density of the outside atmosphere. Consequently this invention provides a differential regulator for maintaining the diflerence between the pressure in conduit I03 and atmospheric pressure constant.

In operation, when the system is in equilibrium the pressure in conduit I03 will be at its proper value with respect to atmospheric pressure. Under these circumstances the pressures within the bell chamber I1, and the counterweights would cause the bell chamber I! at the right,- as seen in Figure 1, to move upwardly slightly;

this would move the arm I5, cross member I2, and

members 44 and'dli in a counter-clockwise diquence of operation of the devise, the bell chamber on the left, as seen in Figure 1, rising and moving portion 41 of lever 42 toward the bleed port in nipple 43, thereby increasing the pressure in conduit 106 and tending to open the'damper I 04. Thus this operation would tend to restore the original pressure differential.

In making adjustments in the control point of the instrument to maintain a different constant pressure or pressure differential, the counterweights I4 may be readjusted on-arm 15 to balance the changed-pressure conditions in the bell chambers. The assembly indicated by numeral 30 and carrying nipple 43 of looped tube 38 may then be bodily adjusted by loosening screw 36 and angularly repositioning assembly 30 about screw 39a as a pivot, screw'3 l assuming a new position with respect to slot 33. Such adjustment provides a new bleed rate for the same angulan. position of members l5, l2, and it which is just suficient for the damper opening necessary to produce the desired balancing pressure in conduit I03.

For providing a sensitivity adjustment the thumb nuts 45 are arranged on either sideof the dog or lever 46 on screw 44. As is apparent, the screw 44 oscillates with cross bar l2 in arm l5. By adjusting the thumb nuts 45 and dog 46 vertically, that is, away from the center of oscillation of screw 44 it will readily be seen that the linear distance moved by dog 46 for the same angular movement of arms l5 and. cross member I2 is increased. The thumb nuts 45 and device the instrument.

From the above description of the structure in operation it will be apparent that the inventionprovides a novel and useful device for maintaining a constant pressure differential between two regions of different pressures ashes been explained. It is also, however, within the contemplation of the invention that the device be utilized to maintain constant a single pressure.

This purpose may be accomplished by sealing the interior of one of the bell chambers'from communication with theoutside atmosphere. The pressure within the tank acting on the exterior of the two bell chambers would be equal on each and would balance. Therefore, changes in atmosphere pressure would have'no effect upon the instrument. Due to the movement of the bells being very slight, the pressure beneath the a sealed bell chamber would be substantially constant and the device would then operate to maintain' the pressure being communicated to theinterior of the other bell chamber constant. In otherwo rds, the device would be acting to govern a single pressure and would be influenced by that pressure only.

' While I prefer to utilize two bells for actuating the control valve, itwill be dersto'od that my invention is not limited, to such sin-arrangement,

for in certain cases, itmay be feasible to utilize v only a single bell.

The structure including thiei' weilswlthin-thef .bell chambers J and the endsof the conduits.

26 which form standpipes within the wells, is

particularly useful in apparatus of this type.

With the type of pressure regulator with which this invention is concerned, inconvenience has frequently been experienced by liquid overflowing into the,upstanding portions of conduit 26 or other similar means providing communication with the region where the pressures to be v overflow of oil into conduits 26 is prevented.-

The screw plugs 21-28 provide for draining any liquid which may overflow into the wells 2|.

Having described the structure and operation of the invention and having pointed out its prin-' cipal novelty, utility, and advantages, it is thought that those skilled in the art will appre- ,ciate its merit and recognize its contribution to the art involving pressure regulators. There are many modifications and variations which ap-' plicant has not made reference to which willoccur to those skilled in the art and it is'intend- 1 "ed that the above description and drawings shall be interpreted as an illustrative embodiment only of the invention and that the scope of the invention is to be limitedonly'by the appended claims.

I claim as my invention.

1. In a pressure regulator a pair of bell floats contacting with a liquid, means providing communication between the interior of each bell float and a separate pressure region, a lever atfulcrum means for/said lever. between said bell floats, said fulcrum means having a knife-edge and a point in spaced relation for supporting said lever whereby said lever oscillates in a single 80 tached to the upper portion of both bell floats,-

plane, adjustable weightsslidably engaging said lever on each side of said fulcrum for counterbalancing the pressures in said bell floats, means actuated by said lever, said lever including means for adjusting the operative relation between said lever and said actuated means, said actuated means having adjustable mounting means.

2. In a device for regulating pressures, in combination, a tank containing a liquid. a floatin said tank and contacting the liquid, means for causing said float to rise and lower upon variationsin pressure at a predetermined point, a lever in said tank, said lever having a fulcrum and being rotated about its fulcrum in 'one direction upon rising of said float and being rotated in the opposite direction upon lowering of said float, an arm attached to said lever adjacent said fulcrum, said arm being substantially normal to both said lever and said fulcrum and oscillating with said lever, control valve means in said tank, said control valve means including a valve lever having a portion extending parallel to' said arm, and a movable member between said valve leverand said arm, said movable member transmitting motion of said arm' to said valve lever, movement of said member along said arm and valve lever varying the ratio 6f movement of said arm to movement of said, valve lever.

3. In adeice for regulating pressures, in comfbination, a tank containing a liquid, a lever struc- 'ture having centrally located fulcrum means, said lever structure carrying a pair of bell floats, one, of said bell floats being attached to said lever structure on one side of said fulcrum means and the other'of said bell floats being atside, of said fulcrum means, said bell floats tached to' said lever structure on the other having open sides extending beneath the surface of said liquid, means for communicates first arm and extending transversely of said first I apropos ing a controlling pressure with the interior of at least one of said bell floats to thereby cause rising and lowering of said one bell float upon rising and lowering of said controlling pressure with consequent oscillation of said lever structure, an arm attached to said lever structure at a point adjacent the axis of the fulcrum means, said arm being substantially normal to both said lever structure and said axis and oscillating with said lever structure, control valve means including' a valve lever having a portion extending parallel to said arm, and a movable member be tween said valve lever and said arm, said movable member transmitting motion of said arm to said valve lever, movement of said member along said arm and valve lever varying the ratio. of movement of said arm to movement of said valve lever.

4. In a device for regulating pressures, in combination, a tank containing a liquid, a lever structure in said tank, said lever structure comprising a first arm, said first arm being supported at one end by a knife edge and at its other end by a point, said knife edge and point being in alignment for providing substantially frictionlessrocking of said lever structure, said lever structure also comprising a second arm attached to said arm, a pair of bell floats attached to said second arm, one of said bell floats being attached to said second arm on one side of said first arm. and the other of said bell floatsbeing attached to said second arm on the other side of said first arm, means for communicating a controlling pressure with the interior of one of said bell floats, a third arm attached to said lever structure and being substantially normal to said first and second arms, control means including a control lever having a portion extending parallel to said third arm, and a movable member between said control lever and said arm, said movable member transmitting motion of said arm to said control lever,

' movement of said member along said third arm 1 arm, a pair 0! bell floats attached to sald'second arm, one of. said bell floats'being attached to said and said control lever varying theratio of moveend by a knife edge and at its other end-by a point, said knife edge and point being in alignment for providing substantially frictionless rocking of said lever structure, said lever structure also comprising a second arm attached to said first arm and extending transversely of said first porting kievlces, at

second arm on one side of said first arm and the other of said bell floats being attached to said,

trolling pressure.

6. In a device for regulating pressures, in combination, a tank containing a liquid, a lever structure in said tank, said lever structure comprising a first arm, said first arm being supported at spaced points by substantially frictionless supleast one of said supporting devices comprising a point engaging a depression in said first arm for preventing both. longitudinal and lateral movement of said first arm while permitting free rocking movement thereof, said lever structure also comprising a second arm attached to said first arm and extending transversely of said first arm, a pair of bell floats attached to said second arm, one of said bell floats beingattached to said second arm on one side of said first arm and the other of said bell floats being attached to said second arm on the; other side of said first arm, means for communicating a controlling pressure with the interior of one of said bell floats, and a control device actuated upon rocking movement of said lever structure'caused by change in value of said controlling pressure.

7. In a device for regulating pressures, in combination, a tank containing a liquid, a lever structure in said tank, said lever structure comprising a first arm, said first arm being supported at spaced po intsby substantially frictionless supporting devices, at least one of said supporting devices comprising a point engaging a depression in said first arm for preventing both longitudinal and lateral movement of said first arm while permitting free rocking movement thereof, said lever structure also comprising a second arm attached to said first arm and extending transversely of said first arm, a pair oi bell floats attached to said second arm, one of said bell floats being attached to said second arm on one side of said first arm and the other of said bell floats being attached to said second arm on the other side of said first arm, means for communicating a controlling pressure with the interior oi. one of said bell floats, a control device actuated upon rocking movement 01 said lever structure caused by change'in value of said controlling pressure, and means for varying the degree of movement of said control device for a given change in value of said controlling pressure.

. JOHN M. LARSON. 

